Internal grip collet



June 12, 1956 s. N. PECZYNSKI 2,750,196

INTERNAL GRIP COLLET Filed June 11, 1953 2 Sheets-Sheet 1 INVENTOR.

S/an/ey/V. p662 y/isk 2' ATTORNEYS.

s. N. PECZYNSKI 2,750,196

INTERNAL GRIP COLLET June 12, 1956 Filed June 11, .1953

2 Sheets-Sheet 2 INVENTOR. Sfa/W/Qy M Pec'z yns/nu' A T TORNEKS INTERNAL GRIP COLLET Stanley N. Peczynski, North Attleboro, Mass.

Application June 11, 1953, Serial No. 360,977

1 Claim. (Cl. 279-2) This invention relates to an internal grip collet of the type for gripping apiece of work by a central opening in the work.

One of the objects of this invention is to provide a simple device for gripping and accurately aligning a piece of work for rotating the same for the performance of further work thereon.

Another object of this invention is to provide a head having a surface at right angles to the axis of rotation of the collet for locating the work with relation to the gripping part of the apparatus.

Another object of the invention is to provide a device in which different size sets of jaws may be utilized and one substituted for the other by a simple operation.

Another object of the. invention is to provide a device which may be easily manipulated in a lathe or other machine tool for holding the work.

Another object of the invention is to provide easily accesible means for manipulating the holding jaws.

With these and other objects in view, the invention consists of certain novel features of construction as will be more fully described and particularly pointed out in the appended claims.

In the accompanying drawings Figure 1 is a central sectional view through the device showing the same as mounted in the bearing portion of a rotating member of a machine tool or the like;

Figure 2 is. a sectional view online 2.--2 of Figure 1;

Figure 3 is. a sectional view on line 33 of Figure 1;

Figure 4 is a sectional view on line 4-4 of Figure 1;

Figure 5 is a sectional view showing a modified form of jaw for the gripping sleeve;

Figure 6 is an elevation of a left-hand end portion of the structure shown in Figure 1 showing a spacing bushing being used to position the work at a different location with reference to the head;

Figure 7 is a face view of a modified form of internal grip collet;

Figure 8 is a sectional View on substantially line 88 of Figure 9;

Figure 9 is a sectional view on line 9-9 of Figure 8.

In proceeding with this invention, I have provided a conical surface along which a sleeve comprising a plurality of jaws may be axially moved so as to expand or contract these jaws depending upon their axial position along this conical surface. Means are also provided for moving the jaws to expand them by means of a screw and nut, the nut being turned by means of a handle portion or mechanical means which enables easy turning.

With reference to the drawings, 10 designates some rotating member such as the head of a lathe or other machine tool in which there is provided a bearing 11. The device of this invention is mounted in this hearing and comprises a body designated generally 12 which will have a tapered shank 13 to fit the tapered surface 14 of the bearing 11. This body is provided with a central bore 15 extending axially through it, while intermediate its ends 1 nit-ed States Patent there is a head 16 having a surface 17 in one side thereof which is in a plane at right angles to the axis of the bore 15. Adjacent the surface 17 there is a projecting portion 18 which has a conical surface 19 concentric with the axis of the bore 15.

A sleeve designated generally 20 (Figure 3) embraces this conical surface and comprises a plurality of separate jaws 21, there being shown four'in the sleeve 20' as here,

illustrated although this number may be varied. This sleeve has a cylindrical outer surface 22, While it has a bore 23 which is conical having the same taper as the conical surface 19 so that as this sleeve slides along the tapered surface 19, the outer surface 22 is maintained cylindrical. The end surface 24 of the sleeve which is composed of the end surfaces of the several jaws is at right angles to the axis of the bore 15 and will be maintained parallel to the surface 17 at all positions of its axial adjustment along the conical surface.

A shaft 25 extends through the bore 15 and is of a size so as to be accurately guided thereby in sliding movement. This shaft has a head 26, the inner surface of which is at right angles to the surface of the bore and the axis of the shaft so that it will truly engage the surface 24' of the sleeve so that axial movement of the shaft will impart axial movement to the jaws through the contacting parallel surfaces. The sleeve is provided with a circumferential recess 46, and an elastic member comprising a helically coiled spring 27 is located in this recess so as to tend to contact the jaws of the sleeve on the conical surface and to hold them in assembled relation therewith.

The inner end 47 of the shaft 25 is threaded and is also provided with a keyway 28 which receives a pin 29 to prevent rotation of the shaft although permitting sliding movement thereof. A nut 30 engages the threaded end of the shaft 25, while its end is maintained spaced from the end of the shank 13 by a washer or shock aosorbing spacer 31 positioned between the ends of the shank 13 and the nut 30. A centralizing bushing 32 is loosely mounted upon the extended nut 30 and may be reduced as at 33 to extend into the bearing 11 so as to mount the nut for "rotation through its shank portion 34. For rotating this nut there is a wheel 35 which has a plurality of openings 36- therein for the reception of a lever, the same beingv locked to the nut by means of a tapered pin 37' anda set screw 38 to hold the pin in place.

In use, a piece of work designated W may be positioned with its end face 40 against the surface 17 and its bore 41 over the sleeve 20. Rotating the wheel 35 so as to draw the shaft 25 to the right, as shown in Figure 1, will move the jaws 21 along the conical surface to expand the sleeve and cause a gripping of the cylindrical surface 22 and the cylindrical bore 41 of the work to lock the work in position so that it may be rotated by the head 10.

In some cases it may be desirable to position a bushing, such as 42 in Figure 6, between the face 17 and the work W so as to locate the work further from the face 17. In some cases the bore 41 and the work may be of such a size that a different sleeve may be desirable, and in this case the set of jaws forming the sleeve may be readily removed by rotating the wheel 35 to loosen the jaws and then expanding the jaws so that they may be taken over the head 26 of the shaft and another set having a different diameter positioned thereon. The outer surface of the jaws 21 may be smooth or may be roughened as at 44, as shown in Figure 5, as occasion may require.

In some cases where it is desired to provide a mechanical means for turning the nut and an arrangement which will fit upon a tapered rotating member, I have provided a modified construction, as shown in Figures 7, 8, and 9.

In these figures the body is designated 50 and comprises a head 51 having faces 52 and 53, each in a plane at right angles to the axis of a central bore 54 extending axially through the body. Outwardly from the face 52 there is a projection 54 having a conical surface 55 which is comparable to the conical surface 19 above described. A sleeve 56 is similar to the sleeve 20 above described and is provided with a plurality of jaws 57 which together provide an outer substantially cylindrical surface 58 which is recessed as at 59 with a helical spring 60 located in the recess and serving to hold the jaws in assembled relation. A bore 61 extends through the sleeve and is tapered on the same taper as the surface 55 so that when the sleeve is slid along the projection 54, the jaws will expand, enlarging the cylindrical surface 58. The sleeve is recessed as at 62 and receives the head 63 of the shaft 64 which is threaded at its inner end as at 65. This shaft 64 is of a size to be accurately guided by the bore 54 through the body. It is keyed to the projection 54' by a set screw 66 in slot 67 in the shaft 64. The head 63 of the shaft has its inner surface parallel to the surfaces 52. and 53 and also parallel to the surface 68 at the bottom of recess 62, which is also parallel to these surfaces. The jaws are keyed to the projection 54' by set screws 69 entering slot 70. Screws 91 extend through slots 92 in head 63 and thread into the jaws 57. Their heads serve to prevent extended relative axial movement of the head 63 and the jaws so the jaws may be moved outwardly for contraction of the sleeve.

A recess 71 is formed in the inner face of the head 51 and receives a nut 72 which threadingly engages the thread of the shaft 64. The hub of this nut engages the bottom 73 of the recess, while a plate 74 engages the outer shoulder 75 of the hub so that axial movement of the nut is prevented. This plate is held across the recess 71 by screws 76. The outer edge of the nut 72 is provided with gear teeth 77 (see also Figure 9) with which a worm '78 engages. This worm has bearings 79 in the bore 80 extending transversely of the head 51 and may be held against axial movement by the spherical enlargement 81 on the shaft 82 of the worm being held in spherical bearing 83 located in recess 84 of the head 51. This bearing is held in place by the threaded cap 85 and the shaft may be turned by the square or hex end 86 which is located within the circumference of the head 51. A U member 87 forming a saddle bearing also engages the shaft and is held in place by a set screw 88 engaging this member 87 which is in a recess 89 swung inwardly from the circumference of the head 51. By rotation of the shaft 82 from 4 flats 86 at one end the nut is rotated to draw the shaft 64 axially through the bore 54 and slide the jaws 57 along the conical surface 61 to expand their circumference and grip the circular hole in a piece of work for holding the same on the collet for rotation.

The outer surfaces of the head 51 are tapered as at 90 so that this head may fit upon the tapered end 91 of some rotating member and be held on such member by bolts or other suitable holding means.

I claim:

An internal grip collet comprising a body portion having a bore therethrough and an external conical surface concentric with the axis of said bore, an outwardly extending head having its face nearest said surface at right angles to the axis of said bore, a sleeve comprising a plurality of jaws having their end surfaces distant from the head parallel to said face and together having a tapered bore to slide along said conical surface and pro gressively change the size of their outer diameter as relative axial movement occurs while maintaining its end surface parallel to said face, key and keyway in said conical surface and sleeve to prevent relative rotation while permitting relative axial movement thereof, a shaft slidable in said bore and having a fixed head engaging the jaws of said sleeve, the engaging surface of said shaft head being at right angles to the axis of said bore and parallel to the end surface of said jaws, and means extending radially of the axis of the bore and means engaging said radial means and accessible through the side of the body to draw said shaft through said bore to expand said sleeve.

References Cited in the file of this patent UNITED STATES PATENTS 291,282 Blue Jan. 1, 1884 982,403 Whitton Jan. 24, 1911 1,548,730 Mirfield Aug. 4, 1925 1,944,255 McFall et al Jan. 23, 1934 2,226,078 Spahn Dec. 24, 1940 2,398,278 Bailey Apr. 9, 1946 2,469,873 Ernest May 10, 1949 2,526,772 Reynolds Oct. 24, 1950 FOREIGN PATENTS 15,605 Great Britain Nov. 27, 1884 249,177 Switzerland Mar. 16, 1948 

